Biomass plantations not compatible with planetary boundaries

01/22/2018 - Planting trees or grasses on a grand scale in plantations to extract CO2 from the atmosphere - this could make a long-term contribution to climate protection, but it would push the planet beyond ecological limits in other dimensions. A new study by the Potsdam Institute for Climate Impact Research (PIK) in the journal Nature Climate Change now for the first time establishes a connection between ambitious international climate objectives and the more comprehensive concept of planetary boundaries. If biomass plantations in which plants bind carbon dioxide during growth are massively expanded, this would entail enormous risks for areas that are already stressed, such as biodiversity, biogeochemical flows, water resources and land use. According to the study, biomass as a means to capture and store CO2 can therefore only make a limited contribution. In order to stabilize the climate, a rapid reduction of greenhouse gas emissions from the combustion of coal, oil and gas is crucial.
Biomass plantations not compatible with planetary boundaries

“Limiting global warming to 2 or even 1.5 degrees Celsius is partly linked to the question of whether excess CO2 can be removed from the atmosphere, for example through biomass plantations and Carbon Capture and Storage," explains Vera Heck, lead author of the study. “But how would this massive interference with our biosphere affect other ecological boundaries of the planet? This is what we investigated in this comprehensive study. With the result that CO2 emissions can only be balanced by biomass and Carbon Capture and Storage (CCS) with extensive environmental damage for other planetary boundaries. If, on the other hand, these ecological guidelines were consistently taken into account, the potential for biomass and CCS is very small".

The concept of planetary boundaries encompasses key processes and systems that determine the stability and resilience of the Earth's system and thus shape the environmental conditions that are the foundation of our society today. Some of these boundaries have already been transgressed. “To ensure a safe operating space for mankind, the challenge is to respond to planetary boundaries in context. Protective measures in one area can have negative consequences for another – this is what our study shows very clearly using the example of negative emissions as a possible measure for climate protection. More and more, the very important analysis of the climate problem has to be reflected with the Earth System as a whole in mind”, stresses Wolfgang Lucht, co-author and PIK expert for Earth System Analysis.

“Our work substantiates that it would be highly risky to play only this card as a strategy for achieving the climate targets," adds Dieter Gerten, head of the PIK research group on Planetary Boundaries. “We need a swift shift to sustainable management in agriculture and water use as well, to limit pressure for the global environment. To achieve climate targets in this bigger context, it is therefore essential to reduce CO2 emissions right now, instead of relying on supposedly green technologies that are supposed to make up for a slower pace". 

Article: Vera Heck, Dieter Gerten, Wolfgang Lucht, Alexander Popp (2017): Biomass-based negative emissions difficult to reconcile with planetary boundaries. Nature Climate Change. [DOI: 10.1038/s41558-017-0064-y]

Weblink to the article: http://dx.doi.org/10.1038/s41558-017-0064-y